Why does the basal body temperature drop as soon as the fan or air conditioner blows?

In Physiology published by People's Health Publishing House, the basal body temperature is described as follows: when the human body is awake and very quiet, the state that is not affected by factors such as muscle activity, mental stress, food and environmental temperature is called "basal state", and the body temperature in the basic state is called "basal body temperature", which is usually measured before getting up in the morning. The basal body temperature of women changes with the menstrual cycle. During follicular phase, the body temperature is low, the ovulation day is the lowest, and it rises by 0.3~0.6℃ after ovulation.

20 12 "who handbook of safe period contraception" mentioned that the basal body temperature-the resting body temperature of women of childbearing age will increase slightly after ovulation; Until the next menstrual cramp, the body temperature will be in a very high state. Specific methods: after waking up every day (before getting up to eat anything), measure the body temperature at the same time and record it in a special form; After ovulation, it generally rises by 0.2~0.5℃ (usually in the middle of menstruation).

There are some serious injuries in the traditional measurement method after waking up in the morning, which limits the application scope of this long-standing clinical discovery. For example, there is no guarantee that you will wake up in the same state at the same time every day. The temperature rise measured by traditional methods usually lags behind ovulation (the temperature rises only a few days after ovulation). It is difficult for doctors to judge when to ovulate with some basic clinical thermometers recorded by women, and many doctors will draw many conclusions. Similar to this conclusion, the National Institutes of Health (NICE) comprehensively evaluated the current scientific research literature and concluded that "any product based on basal body temperature measurement cannot reliably predict ovulation, and it is not recommended to confirm ovulation date."

At present, there are products that predict ovulation day by measuring body temperature all night. From a published paper, it can be seen that for infertile women with regular menstrual cycle, compared with B-ultrasound to detect follicular size, (continuous overnight temperature measurement) can accurately predict ovulation date and ovulation cycle.